As someone who drives this route every single day, I wanted to point out a few missing facts to the cause of the congestion.
1) Some of the congestion is due to the intersection because you get trucks turning left in front of Eastbound SFPR on red lights. Not just going through a light turning red, I mean it is already red. I've sat eastbound and our light goes green and a truck in the left turn just turns right in front of everyone.
I still stand by the notion that if you stationed a cop at that intersection every single day, they'd write about $20,000 in tickets every day.
2) The backups for the left-turn (what causes all the trucks and cars to run the red) is actually not a result of the intersection at SFPR but rather a result of the 1 lane overpass + left turn design of the connector to get onto the Alex Fraser bridge.
People line up trying to turn left onto HWY91 onto the Alex Fraser and as the overpass is 1 lane from the SFPR (and actually is like 3 lanes into 1 lane) everyone gets stuck and that lines up all the way to the SFPR.
So then people turning left off SFPR get stuck. It can take you 30 minutes (I kid you not) to get from the left lane from SFPR Westbound to the Alex Fraser bridge. Something that with no traffic takes about 2 minutes.
See the following image for the problem points. Bottom arrow is where 3 lanes --> 1 lane over the overpass. Second arrow is the left turn across Nodel to get on the AFB that backs up causing even people that just want to go straight through to get stuck behind all the left-turners on the overpass. Also keep in mind you have a truck weigh scale on the other side of the overpass so 23723928 trucks along that stretch which are slow and can't turn very quickly.
My fear is that with an interchange you will solve Eastbound issues but Westbound will compound even worse because trucks again getting off and onto the connector to Alex Fraser will line up onto the highway westbound at the exit. Similar to what happens at Steveston through the tunnel. It will line up through the tunnel in the right lane in rush-hour just because of people stuck trying to exit at Steveston.
So they really need to not just put an interchange at SFPR there but also need to widen the overpass over HWY91 and remove the left turn across Nordel making it a proper interchange onto AFB.